cmd/compile, go/importer: minor cleanups

Change-Id: Ic7a1fb0dbbf108052c970a4a830269a5673df7df
Reviewed-on: https://go-review.googlesource.com/21963
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

diff --git a/src/cmd/compile/internal/gc/bexport.go b/src/cmd/compile/internal/gc/bexport.go
index e780bcf5777850806f5a324e07d2d12100d46dc7..59a85c2f23e5d7eb4985bb2e4168e0086c2ca52e 100644 (file)
--- a/src/cmd/compile/internal/gc/bexport.go
+++ b/src/cmd/compile/internal/gc/bexport.go
@@ -59,9 +59,8 @@ Encoding format:
 
 The export data starts with a single byte indicating the encoding format
 (compact, or with debugging information), followed by a version string
-(so we can evolve the encoding if need be), the name of the imported
-package, and a string containing platform-specific information for that
-package.
+(so we can evolve the encoding if need be), and then the package object
+for the exported package (with an empty path).
 
 After this header, two lists of objects and the list of inlined function
 bodies follows.

diff --git a/src/cmd/compile/internal/gc/bimport.go b/src/cmd/compile/internal/gc/bimport.go
index 2e80b9f81d2ebbced7df570f86868f61d6599387..4a93b5a91dfc2ac35615bcb83691f02197095db2 100644 (file)
--- a/src/cmd/compile/internal/gc/bimport.go
+++ b/src/cmd/compile/internal/gc/bimport.go
@@ -59,9 +59,6 @@ func Import(in *bufio.Reader) {
 
        // read package data
        p.pkg()
-       if p.pkgList[0] != importpkg {
-               Fatalf("importer: imported package not found in pkgList[0]")
-       }
 
        // defer some type-checking until all types are read in completely
        // (parser.go:import_package)
@@ -193,7 +190,12 @@ func (p *importer) pkg() *Pkg {
                Fatalf("importer: bad path in import: %q", path)
        }
 
-       // an empty path denotes the package we are currently importing
+       // an empty path denotes the package we are currently importing;
+       // it must be the first package we see
+       if (path == "") != (len(p.pkgList) == 0) {
+               panic(fmt.Sprintf("package path %q for pkg index %d", path, len(p.pkgList)))
+       }
+
        pkg := importpkg
        if path != "" {
                pkg = mkpkg(path)

diff --git a/src/go/internal/gcimporter/bimport.go b/src/go/internal/gcimporter/bimport.go
index 81af064b88b4836995ec590f8c02483e84b4091e..7a7bc871f4cefa9c1d3c8539447f840679a51e3d 100644 (file)
--- a/src/go/internal/gcimporter/bimport.go
+++ b/src/go/internal/gcimporter/bimport.go
@@ -16,12 +16,15 @@ import (
 )
 
 type importer struct {
-       imports  map[string]*types.Package
-       data     []byte
+       imports map[string]*types.Package
+       data    []byte
+       path    string
+
        buf      []byte   // for reading strings
        bufarray [64]byte // initial underlying array for buf, large enough to avoid allocation when compiling std lib
-       pkgList  []*types.Package
-       typList  []types.Type
+
+       pkgList []*types.Package
+       typList []types.Type
 
        debugFormat bool
        read        int // bytes read
@@ -35,6 +38,7 @@ func BImportData(imports map[string]*types.Package, data []byte, path string) (i
        p := importer{
                imports: imports,
                data:    data,
+               path:    path,
        }
        p.buf = p.bufarray[:]
 
@@ -58,25 +62,7 @@ func BImportData(imports map[string]*types.Package, data []byte, path string) (i
        p.typList = append(p.typList, predeclared...)
 
        // read package data
-       // TODO(gri) clean this up
-       i := p.tagOrIndex()
-       if i != packageTag {
-               panic(fmt.Sprintf("package tag expected, got %d", i))
-       }
-       name := p.string()
-       if s := p.string(); s != "" {
-               panic(fmt.Sprintf("empty path expected, got %s", s))
-       }
-       pkg := p.imports[path]
-       if pkg == nil {
-               pkg = types.NewPackage(path, name)
-               p.imports[path] = pkg
-       }
-       p.pkgList = append(p.pkgList, pkg)
-
-       if debug && p.pkgList[0] != pkg {
-               panic("imported packaged not found in pkgList[0]")
-       }
+       pkg := p.pkg()
 
        // read objects of phase 1 only (see cmd/compiler/internal/gc/bexport.go)
        objcount := 0
@@ -91,7 +77,7 @@ func BImportData(imports map[string]*types.Package, data []byte, path string) (i
 
        // self-verification
        if count := p.int(); count != objcount {
-               panic(fmt.Sprintf("importer: got %d objects; want %d", objcount, count))
+               panic(fmt.Sprintf("got %d objects; want %d", objcount, count))
        }
 
        // ignore compiler-specific import data
@@ -135,16 +121,22 @@ func (p *importer) pkg() *types.Package {
                panic("empty package name in import")
        }
 
-       // we should never see an empty import path
-       if path == "" {
-               panic("empty import path")
+       // an empty path denotes the package we are currently importing;
+       // it must be the first package we see
+       if (path == "") != (len(p.pkgList) == 0) {
+               panic(fmt.Sprintf("package path %q for pkg index %d", path, len(p.pkgList)))
        }
 
        // if the package was imported before, use that one; otherwise create a new one
+       if path == "" {
+               path = p.path
+       }
        pkg := p.imports[path]
        if pkg == nil {
                pkg = types.NewPackage(path, name)
                p.imports[path] = pkg
+       } else if pkg.Name() != name {
+               panic(fmt.Sprintf("conflicting names %s and %s for package %q", pkg.Name(), name, path))
        }
        p.pkgList = append(p.pkgList, pkg)